diff options
Diffstat (limited to 'drivers/mfd/twl6030-pwm.c')
| -rw-r--r-- | drivers/mfd/twl6030-pwm.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/mfd/twl6030-pwm.c b/drivers/mfd/twl6030-pwm.c new file mode 100644 index 00000000..e8fee147 --- /dev/null +++ b/drivers/mfd/twl6030-pwm.c @@ -0,0 +1,165 @@ +/* + * twl6030_pwm.c + * Driver for PHOENIX (TWL6030) Pulse Width Modulator + * + * Copyright (C) 2010 Texas Instruments + * Author: Hemanth V <hemanthv@ti.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/i2c/twl.h> +#include <linux/slab.h> + +#define LED_PWM_CTRL1 0xF4 +#define LED_PWM_CTRL2 0xF5 + +/* Max value for CTRL1 register */ +#define PWM_CTRL1_MAX 255 + +/* Pull down disable */ +#define PWM_CTRL2_DIS_PD (1 << 6) + +/* Current control 2.5 milli Amps */ +#define PWM_CTRL2_CURR_02 (2 << 4) + +/* LED supply source */ +#define PWM_CTRL2_SRC_VAC (1 << 2) + +/* LED modes */ +#define PWM_CTRL2_MODE_HW (0 << 0) +#define PWM_CTRL2_MODE_SW (1 << 0) +#define PWM_CTRL2_MODE_DIS (2 << 0) + +#define PWM_CTRL2_MODE_MASK 0x3 + +struct pwm_device { + const char *label; + unsigned int pwm_id; +}; + +int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) +{ + u8 duty_cycle; + int ret; + + if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) + return -EINVAL; + + duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1); + + if (ret < 0) { + pr_err("%s: Failed to configure PWM, Error %d\n", + pwm->label, ret); + return ret; + } + return 0; +} +EXPORT_SYMBOL(pwm_config); + +int pwm_enable(struct pwm_device *pwm) +{ + u8 val; + int ret; + + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); + if (ret < 0) { + pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret); + return ret; + } + + /* Change mode to software control */ + val &= ~PWM_CTRL2_MODE_MASK; + val |= PWM_CTRL2_MODE_SW; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); + if (ret < 0) { + pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret); + return ret; + } + + twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); + return 0; +} +EXPORT_SYMBOL(pwm_enable); + +void pwm_disable(struct pwm_device *pwm) +{ + u8 val; + int ret; + + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); + if (ret < 0) { + pr_err("%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return; + } + + val &= ~PWM_CTRL2_MODE_MASK; + val |= PWM_CTRL2_MODE_HW; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); + if (ret < 0) { + pr_err("%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return; + } + return; +} +EXPORT_SYMBOL(pwm_disable); + +struct pwm_device *pwm_request(int pwm_id, const char *label) +{ + u8 val; + int ret; + struct pwm_device *pwm; + + pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); + if (pwm == NULL) { + pr_err("%s: failed to allocate memory\n", label); + return NULL; + } + + pwm->label = label; + pwm->pwm_id = pwm_id; + + /* Configure PWM */ + val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC | + PWM_CTRL2_MODE_HW; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); + + if (ret < 0) { + pr_err("%s: Failed to configure PWM, Error %d\n", + pwm->label, ret); + + kfree(pwm); + return NULL; + } + + return pwm; +} +EXPORT_SYMBOL(pwm_request); + +void pwm_free(struct pwm_device *pwm) +{ + pwm_disable(pwm); + kfree(pwm); +} +EXPORT_SYMBOL(pwm_free); + +MODULE_LICENSE("GPL"); |